R-bodies of human rectal epithelial cells.

Distinctive globular bodies, ranging in diameter from 0.2mu to 1.5mu, were encountered in the cytoplasm of epithelial cells of human rectal mucosa. These profiles, surrounded by a unit membrane, contained a uniform population of electron-dense rods 50 nm wide and 100 to 250 nm long. Although neither the origin nor the relationships of these rod-containing bodies (R-bodies) to other cytoplasmic organelles could be established, morphologic and cytochemical studies demonstrated clear differences from multivesicular bodies.